下列运算正确的是( )A、x3+x3=2x6     B、x6÷x2=x4      C、xm•xn

下列运算正确的是(  )

A、x3+x3=2x6     B、x6÷x2=x4      C、xm•xn=xnm     D、(-x53=x15

 

答案

B

 解析:x3+x3=2,故A错;x6÷x2=x4,同底数幂相除,底数不变,指数相减,故B对;xm•xn=,同底数幂相乘,底数不变,指数相加,故C错;(-x53= -x15,故D错。 选B

 

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